<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>过渡实战1</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .box {
            width: 1200px;
            overflow: hidden;
            margin: 40px auto;
        }

        .box ul {
            list-style: none;
        }

        .box ul li {
            float: left;
            width: 380px;
            height: 210px;
            margin-right: 20px;
            position: relative;
        }

        .box ul li img {
            width: 380px;
            height: 210px;
        }

        .box ul li .info {
            position: absolute;
            width: 370px;
            height: 30px;
            color: white;
            line-height: 30px;
            bottom: 0;
            padding-left: 10px;
            background-color: rgba(0, 0, 0, .5);
            /*透明度设置为0*/
            opacity: 0;
            transition: opacity 1s linear 0s;
        }

        .box ul li:hover .info {
            opacity: 1;
        }
    </style>
</head>
<body>
<div class="box">
    <ul>
        <li>
            <img src="images/0.jpg" alt="">
            <div class="info">北京的故宫</div>
        </li>
        <li>
            <img src="images/1.jpg" alt="">
            <div class="info">国家大剧院</div>
        </li>
        <li>
            <img src="images/2.jpg" alt="">
            <div class="info">十七孔桥</div>
        </li>
    </ul>
</div>
</body>
</html>